The present invention relates to a preceding vehicle follow-up control system for enabling a controlled vehicle to recognize a preceding vehicle and to follow up the preceding vehicle while keeping a vehicle-to-vehicle distance.
Japanese Patent Provisional Publication No. 10-272963 has disclosed a typical preceding vehicle follow-up control apparatus which executes a follow-up of a preceding vehicle on the basis of a vehicle-to-vehicle distance and a relative speed.
This conventional preceding vehicle follow-up control apparatus is basically arranged to bring the vehicle-to-vehicle distance closer to a target distance by employing a simply control and to limit acceleration and deceleration of the controlled vehicle for the purpose of improving riding quality in various situations.
However, the limits of the acceleration and the deceleration are generally set at predetermined values, respectively, and therefore it is difficult that these limits suitably function in both a high vehicle speed range and a low vehicle speed range.
It is therefore an object of the present invention to provide a preceding vehicle follow-up control system which enables a vehicle speed control matched with the a drive feeling of a driver by setting a target acceleration/deceleration according to a traveling condition of the controlled vehicle.
A preceding vehicle follow-up control system according to the present invention is for a vehicle and comprises a vehicle-to-vehicle distance detector, a vehicle speed detector and a controller. The vehicle-to-vehicle distance detector detects a distance between a controlled vehicle and a preceding vehicle and outputs a signal indicative of the vehicle-to-vehicle distance to the controller. The vehicle speed sensor detects a vehicle speed of the controlled vehicle and outputs a signal indicative of the vehicle speed to the controller. The controller comprises a vehicle-to-vehicle distance controlling section and a vehicle speed controlling section. The vehicle-to-vehicle distance controlling section calculates a target vehicle speed for bringing the vehicle-to-vehicle distance closer to a target vehicle-to-vehicle distance, on the basis of the vehicle-to-vehicle distance and the vehicle speed. The vehicle speed controlling section controls driving force of the controlled vehicle at a target driving force so as to bring the controlled-vehicle speed closer to the target vehicle speed. The vehicle speed controlling section calculates target acceleration for the target driving force on the basis of the target vehicle speed and limits the target acceleration according to the controlled-vehicle speed.